World Metrology Day is an international observance celebrated annually on May 20. The day highlights the role of measurement science (metrology) in science, technology, economics and societal applications. Metrology ensures the accuracy and reliability of measurements, providing order and consistency across fields ranging from scientific research to international trade, environmental monitoring and public health. The aim of World Metrology Day is to draw attention to the importance of metrology for societies and global processes and to raise awareness.
History
The origins of World Metrology Day trace back to the Metre Convention, signed in Paris on May 20, 1875. This convention established a foundation for internationally comparable measurements and led to the creation of the International Bureau of Weights and Measures (BIPM). Over time, the Metre Convention facilitated the development and global adoption of the International System of Units (SI).
World Metrology Day was officially proclaimed in 1999 by the International Committee for Weights and Measures (CIPM) to commemorate the signing of the Metre Convention. In 2023, UNESCO’s 42nd General Conference (42 C/22) included World Metrology Day among UNESCO International Days. The conference decision emphasized the role of metrology in sustainable development, energy and public health and encouraged member states, civil society organizations and academic institutions to celebrate the day annually.
Global Celebrations and Activities
World Metrology Day is celebrated worldwide by national metrology institutes, legal metrology authorities, regional organizations and international scientific networks. Activities include symposiums, panel sessions, laboratory demonstrations and educational programs. The celebrations emphasize the importance of accurate measurements for economic progress, technological applications and scientific advancement.
The 2025 World Metrology Day was celebrated with the theme “150 Years of the Metre Convention: Science, Innovation, and Global Impact” at a symposium held at the UNESCO Headquarters in Paris. Government representatives, scientists, industry experts and international organizations attended the event. Discussions focused on the significance of harmonized measurement standards for technological progress, economic growth and sustainable development.
Importance of Metrology
Metrology provides the foundation for scientific, technological and economic processes by ensuring measurement accuracy and comparability. Measurement accuracy enables comparability and reproducibility of experimental results. In industry and trade, product quality, safety and fair competition in international markets rely on measurement standards. In health, accurate measurements are critical for drug dosages, calibration of medical devices and laboratory testing. Environmental monitoring, such as climate change data, depends on precise metrological measurements. In transportation and construction, structural safety, engineering calculations and material control require reliable measurement systems. Metrology ensures the continuity and universality of the metric system, allowing international production, design and analysis processes to operate under consistent standards.
UNESCO’s Activities in Metrology
UNESCO associates metrology with scientific advancement, technological development, cultural heritage preservation, and sustainable development. The organization supports the role of measurement science in research, innovation and economic development. Metrological instruments provide data for monitoring historical structures, assessing environmental impacts and implementing preservation processes. UNESCO’s Recommendation on Open Science encourages access to measurement data and promotes international information sharing. The Fundamental Sciences Programme aims to strengthen education, research and international coordination in the field of metrology.
World Metrology Day in Türkiye
In Türkiye, activities are conducted by the TÜBİTAK National Metrology Institute (UME). The 2024 World Metrology Day poster was designed by TÜBİTAK UME in collaboration with the European Association of National Metrology Institutes (EURAMET). The poster, prepared with a sustainability theme, has been used in international events.
